Beginners Guide to Intermittent Fasting

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Intermittent fasting can vary in terms of how many hours or days one fasts and doesn't fast. It can be modified to as little as a 12-hour fasting window or extended to a 20-hour fasting window.

Intermittent fasting has tons of potential benefits and very little drawbacks. If you’ve heard about or are considering intermittent fasting, here’s an overview, tips for getting started and how to modify it to make it work with your lifestyle.

Benefits of Intermittent Fasting

Potential benefits include improved energy, mental clarity and concentration, as well as better blood sugar and insulin levels. Intermittent fasting is also shown to improve cholesterol, blood pressure, body fat, metabolic rate and is linked to reduction in risk factors for Alzheimer’s.

Timing of Intermittent Fasting

Intermittent fasting includes a daily fast, going 18 hours from your last meal of the day until your first meal of the following day. The last meal of your day should be at least three hours before bedtime. During the six-hour window of “eating time,” you’ll have two to three small meals.


Keep a journal during the month, including a log of food and drink, as well as notes about weight (optional), energy, mood, focus, analytical thinking and creativity.


We encourage you to modify intermittent fasting if needed to fit your lifestyle. If the full 18-hour daily fast is too intense (and we get it), try to incorporate one or all of the following three strategies to reap at least some of fasting’s benefits:

  1. Three-hour window before bedtime. Leave at least three hours between your last meal or snack of the evening and bedtime. This has been shown to reduce insulin levels and improve risk factors related to Alzheimer’s.
  2. 12 hours each night. In addition to leaving three hours between your last meal/snack and bedtime, a 12-hour overnight fast helps induce ketogenesis, reduce insulin and reduce the main component of the amyloid plaques in the brain that are linked to Alzheimer’s.
  3. Sugar, white carbs and artificial sweetener fast. If extended fasting is too daunting, a stepping stone can be to “fast” from sugars, white carbs and artificial sweeteners for a month. The goal is to break and replace habits by the time the fast is over.

What’s Allowed and Not Allowed During Intermittent Fasting

Not allowed:

  • Artificial sweeteners
  • Added sugars (honey, agave, etc.)
  • White, refined and processed carbs (white breads, potatoes, pasta, rice, etc.)
  • Alcohol is discouraged

Allowed during the 18-hour fasting period:

  • Water and sparkling water
  • Unsweetened tea
  • Coffee
  • Chicken broth or vegetable broth

Allowed during the six-hour eating period:

Real, whole foods including:

  • Lean proteins
  • Plant-based fats
  • Vegetables
  • Fresh-pressed vegetable juices
  • Fresh fruits
  • Whole grains and legumes
  • Bone broth: different from regular broth or stock in that it’s protein-rich and so technically is not part of a true “fast” – but if sipping bone broth throughout your 18-hour fasting period helps with compliance, then add it in
  • Low-fat plain Greek yogurt
  • Unsweetened almond milk

Who Should Not Fast

Fasting is not for everyone and is not recommended for people with eating disorders or history of eating disorders, those who are malnourished or underweight, people younger than 18 and pregnant or breastfeeding women. People with gout, reflux disease or who take prescription medications should check with their physician before fasting; any person taking medication that the prescriber wants taken with food should not participate in this fasting protocol.

If you have type 1 or 2 diabetes, always check with your doctor before beginning any type of fasting protocol. Individuals with diabetes who are taking insulin are advised not to participate in this type of fasting protocol. If you cannot work closely with your medical team to monitor blood sugar levels and adjust medications accordingly, do not fast.

A version of this article originally appeared on WGNO. See the full article here.

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